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31.
Vertebral column pathologies requiring surgical intervention have been described in pet ferrets, however little information is available on the normal vertebral formula and congenital variants in this species. The purpose of this retrospective study was to describe vertebral formulas and prevalence of congenital vertebral anomalies in a sample of pet ferrets. Radiographs of 172 pet ferrets (96 males and 76 females) were included in this retrospective study. In 143 ferrets (83.14%), five different formulas of the vertebral column were recorded with normal morphology of vertebrae (rib attachment included) but with a variable number of thoracic (Th), lumbar (L), and sacral (S) vertebrae. The number of cervical (C) vertebrae was constant in all examined animals. Observed vertebral formulas were C7/Th14/L6/S3 (51.74%), C7/Th14/L6/S4 (22.10%), C7/Th14/L7/S3 (6.98%), C7/Th15/L6/S3 (1.74%), and C7/Th15/L6/S4 (0.58%). Formula C7/Th14/L6/S4 was significantly more common in males than in females (P < 0.05). Congenital spinal abnormalities were found in 29 ferrets (16.86%), mostly localized in the thoracolumbar and lumbosacral regions. The cervical region was affected in only one case. Transitional vertebrae represented the most common congenital abnormalities (26 ferrets) in the thoracolumbar (13 ferrets) and lumbosacral regions (10 ferrets) or simultaneously in both regions (three ferrets). Other vertebral anomalies included block (two ferrets) and wedge vertebra (one ferret). Spina bifida was not detected. Findings from the current study indicated that vertebral formulas may vary in ferrets and congenital abnormalities are common. This should be taken into consideration for surgical planning.  相似文献   
32.
Tests were conducted by the Agricultural Engineering Staff at North Dakota State University, Fargo, North Dakota, during the summer of 1970 to evaluate the production of carbon monoxide gas due to internal combustion engine operation in warehouses. Tests compared gasoline engines and LP gas engines, equipped with regular and catalytic mufflers and with the fuel system at normal and 10% rich air-fuel ratios. The engines were operated on a cycle of load and no load conditions to approximate actual usage. Exhaust gases were piped to a 10,000 cubic foot sealed room and intake air was taken from the same room. Gas from the test room was sampled periodically and analyzed for carbon monoxide and other gases. A method was devised to estimate the probable CO levels in a warehouse, knowing the volume and infiltration rate of the warehouse and the specific engine being used in the warehouse. For the test conditions:
  1. The LP gas engine produced 50% less CO than the gasoline engine.
  2. The catalytic muffler reduced CO by 40% when compared with a conventional muffler.
  3. Engines set at normal A-F ratios produced 42% less CO than engines set 10% rich.
  相似文献   
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Purpose

Plant growth-promoting rhizobacteria (PGPRs) synthesizes and exports phytohormones which are called plant growth regulators (PGRs). These PGRs may play a regulatory role in plant growth and development. PGRs are organic substances that influence physiological processes of plants at extremely low concentrations. The objective of this study was to find out whether three PGRs, cytokinins, ethephon, and chlorocholine, have a stimulatory or inhibitory effect on the activity of native proteases in soil.

Materials and methods

A revised methodology was used to determine soil protease activity, where TRIS-HCl buffer was replaced with demineralized water. This is described as native protease activity as its activity is not affected by chemicals. The aim was to approximate the protease response to cytokinins in the native soil environment. The native soil proteolytic activity was determined spectrophotometrically.

Results and discussion

The present paper shows that cytokinin, ethephon, and chlorocholine chloride negatively affect the native proteolytic activity of forest soils with the exceptions of the organic and organomineral horizons of European beech (Fagus sylvatica L.) on a rendzic Leptosol. In addition, 6-benzylaminopurine stimulates the native proteolytic activity of the organic horizon of pedunculate oak (Quercus robur L.). A negative effect of cytokinins on the soil proteolytic activity can decrease the rate of organic matter decomposition. The results provide soil biochemists with an insight into the roles of rhizospheric substances on soil microbial activity.

Conclusions

This work has shown that cytokinins and PGRs inhibit the activity of native soil proteases in most of the studied forest sites. Results describe the effect of rhizospheric compounds on the activity of soil microorganisms, with potentially significant implications for the nitrogen cycle in forest soils.

  相似文献   
36.

Purpose

Soil organic matter (SOM) plays an important role in terrestrial ecosystems and agroecosystems. Changes in the agricultural sector in the Czech Republic within the past 25 years have had a negative impact on SOM content and contribute to gradual soil degradation. The aim of this study is to estimate the effect of long-term application of different mineral fertilizers (NPK) and organic manures (manure, cattle slurry) on soil chemical properties (quality of humus, available nutrients, and soil reaction).

Materials and methods

Soil samples were collected from Luvisol during two selected periods 1994–2003 and 2014–2016 from long-term field experiment carried out in Prague-Ruzyně (Czech Republic). Average annual temperature is 8.5 °C, and annual precipitations are 485 mm. Different fertilization regimes have been applied for 62 years. The crop rotation was as follows: cereals (45%), root crops (33%) and legumes (22%). Soil analysis—soil organic carbon (SOC) was determined by oxidimetric titration method. Short fractionation method for evaluation of humic substance (HS), humic acid (HA) and fulvic acid (FA) content was used. Absorbance of HS in UV-VIS spectral range was measured by Varian Carry 50 Probe UV-VIS spectrometer. Degree of humification (DH) and color index (Q4/6) were calculated from fractional composition data. Soil reaction was measured by potentiometric method. Available nutrients (phosphorus, potassium, magnesium, calcium) were determined by Mehlich II and Mehlich I methods and by ICP-OES. For data analysis, the following are used: exploratory data analysis, ANOVA, and principal component analysis (PCA).

Results and discussion

PCA analysis differentiated fertilizers into two categories: (1) variant NPK (lower quality of humus)—higher acidity, lower SOC and HS content, predomination of FA, higher DH and lower content of available nutrients; (2) variants with organic manures (higher quality of humus)—lower acidity, higher SOC and HS content, predomination of HA, middle DH, and high content of available nutrients. The main result of presented study is to give a synthesis of effect of different type of fertilizers on a sustainable organic matter management in arable soils, with respect to yields, food security and adaptation to predict climate changes.

Conclusions

Long-term application of mineral fertilizers (NPK) without organic matter input can accelerate humus mineralization and soil quality degradation with all negative consequences such as (nitrogen leaching, higher availability of toxic element for plants, slow energy for soil microorganisms etc.). Application of organic fertilizers (manure and cattle slurry) helps to achieve the long-term stable yields while maintaining soil at optimum quality (long-term sustainable management with SOM). Principal component analysis is a useful tool for evaluation of soil quality changes.
  相似文献   
37.
The mountain spruce forests of the Western Carpathians have experienced a dramatic deterioration in the last decades increasing the landscape fragmentation. This considerably affected the Western capercaillie population recently surviving within small habitat patches surrounded by unfavourable habitats. Our study shows that the long-term isolation resulted in genetic differentiation with decreasing trend in allelic richness towards the most adjacent western subpopulations. We evaluated dispersal possibilities within the landscape and identified barriers and the most critical corridors between genetically distinct subpopulations. Landscape genetic analysis confirmed that the isolation by environmental features explains the observed genetic patterns better than straight geographical distance. We highlight the urgent need for an active conservation management in the critical habitats where dispersion might be constrained or “bottlenecked” in order to ensure gene flow within the fragmented capercaillie metapopulation of the Western Carpathian mountain forests.  相似文献   
38.
The soil proteolytic complex plays an important role within mineral nutrient cycling in ecosystems. Both auxins and proteases are produced by soil microbiota, and reciprocally, their activities affect the metabolic role of biota in soil. The objective of this study was to find out whether auxins (indole‐3‐acetic acid, indole‐3‐butyric acid, 1‐naphthaleneacetic acid and 2‐naphthoxyacetic acid) have a stimulatory or inhibitory effect on the activity of native proteases in soil. The results presented here demonstrate the positive effect of auxins on the native proteolytic forest soil activity. For example, in organic Oe horizons synthetically produced auxins stimulated native proteolytic activity in the European beech stands, where NOA led to the highest increase in L‐tyrosine production (from 564.02 µg at 0 µg auxin to 645.19 µg at the auxin dose of 100 µg). Comparing organic and organomineral horizons, auxins promote a higher stimulation of protease activity in the organic horizons. Comparing the different forest stands, auxins promote a high stimulation of protease activity in European beech stands. In the organomineral soil horizons, auxins promote a high stimulation of protease activity in Leptosols in European beech stands and Cambisols in pedunculate oak stands. The results confirmed the interrelationships between auxins and the native proteolytic forest soil activity from the viewpoint of dead organic matter decomposition. Furthermore, the general importance of substances produced in the rhizosphere for nitrogen cycling was verified.  相似文献   
39.
Out of six isolates of coccidia of the species Eimeria tenella, obtained in the years 1984 and 1985 on farms with a stationary occurrence of coccidiosis, five were found to have reduced sensitivity or resistance to monensin. Neither were these isolates sensitive to further monovalent ionophorous anticoccidials narasin and salinomycin. The bivalent ionophorous anticoccidial lasalocid controlled five isolates completely, but for one its effectiveness was reduced. An isolate obtained on a farm with long-term absence of coccidiosis was sensitive to all anticoccidial drugs.  相似文献   
40.
Development of the general ecological model (EM) of the CSSR has been included in the state program for environmental policy - the Ecoprogramme of the CSSR — at a scale of 1:1 000 000 for the entire Czechoslovak territory and at a scale of 1:500 000 for the Czech Socialist Republic (CSR) and the Slovak Socialist Republic (SSR). The objective of the first EM stage was to make a survey of spatial differentiation of the major ecological problems of the country. The EM consists of four parts, three analytical and one synthetic. These parts are:
  1. The ecological state (value) of the current spatial structure of the landscape.
  2. Ecological stress factors in the landscape.
  3. Protection of nature and natural resources. From the spatial synthesis of these three groups (from their spatial encounters), the following synthetic group of conditions was obtained:
  4. Regional ecological problems, a system of ecologically stable areas, environmental stress factors and factors endangering the ecological stability of the landscape, the natural resources and the human environment.
  相似文献   
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